Ailerons and rudders must be freely tilted in order to modify the trajectory of the aircraft. They are therefore pivoted to the structures which bear them by hinges. In general, common type hinges are used, comprising a pivot which is fixed to the load-bearing structure, with which the movable panels engage by rotational pins. The orientation of the panels is determined by the control system for the actuators such as cylinders, the opposite ends of which are pivoted to the panels and to the load-bearing structure, a lever arm being formed on the panels between the axis of rotation and the pivot point of the actuator. It could be considered, however, that the hinges are relatively bulky and heavy. Precautions also have to be taken against the possibility of jamming, since certain hinges have to be used simultaneously in practice in order to support each of the panels, by distributing them over the connection line between the panel and the load-bearing structure: the alignment between the axes of the hinges must be respected perfectly, which makes it necessary to construct one fixed hinge and the others floating, that is to say with play. The freedom, however, has to be reconciled with the need to hold the panel against excessive movements due to aerodynamic forces or gravity, which makes it necessary to add stop devices and makes the assembly more complicated.
A simplified device has been proposed in document U.S. Pat. No. 5,463,794 A and consists in a hinge which comprises a flexible plate, the opposite ends of which are embedded in the load-bearing structure and the panel. A pivot point is formed on the hinge indenting it at its middle, so as to give it a reduced thickness locally. The actuators therefore cause the plate to deform appreciably by making it take up variable angles, the apex of which coincides with the location of the indentation. The design hardly seems admissible, however, since the angles formed by the plate have to remain very small in order to avoid plastic mechanical constraints around the indentation. There is also a risk of either fatigue cracking in the case of metal plates, or delamination in the case of composite plates which are formed by stacked layers.